Gas charging valve for accumulator

ABSTRACT

This invention relates to the art of pressure vessels and more particularly to a valve assembly for use in a pressure vessel of the type having a rigid container with a deformable bladder therein, dividing the container into two variable volume chambers, one adapted to receive gas under pressure and the other to receive liquid under pressure. 
     The valve assembly which is screwed into a port in communication with the gas chamber includes a slidably mounted stem having a resilient valve member at one end normally urged to seat on the beveled inner end of an axial bore in the valve assembly in a first seating position of the valve member, and urged further into said beveled inner end when the bladder is charged with gas under pressure in a second seating position of the valve member. The inward movement of the valve member is limited by a stop carried by the stem. When the liquid chamber is charged, if the bladder should abut against the resilient valve member, no extrusion of the bladder would occur.

As conducive to an understanding of the invention, it is to be notedthat where a pressure vessel of the above type is charged with gas underpressure through a conventional gas valve such as a Schrader valve, andthe inner end of the bore in which the Schrader valve is positioned isexposed, when the liquid chamber is charged with fluid under pressure,causing the bladder to deform and extrude into said gas port, cutting ofthe bladder may occur with resultant failure of the unit.

It is accordingly among the objects of the invention to provide a gascharging valve assembly which may be incorporated into a single housingand which has relatively few parts which may readily be fabricated atlow cost, and which will provide a resilient closure at the inner end ofthe gas charging bore against which the bladder may abut, therebypreventing extrusion of the bladder into the gas charging bore withresultant cutting of the bladder and failure of the unit.

According to the invention these objects are accomplished by thearrangement and combination of elements hereinafter described and moreparticularly recited in the claims.

In the accompanying drawings in which are shown one of various possibleembodiments of the several features of the invention:

FIG. 1 is a perspective view of a pressure vessel incorporating theinvention;

FIG. 2 is a sectional longitudinal view on an enlarged scale taken alongline 2--2 of FIG. 1, showing the valve member in closed but unstressedcondition;

FIG. 3 is a transverse sectional view with parts broken away taken alongline 3--3 of FIG. 4;

FIG. 4 is a transverse sectional view taken along the line 4--4 of FIG.3 showing the valve member in closed stressed condition;

FIG. 5 is a detail transverse sectional view taken along line 5--5 ofFIG. 4, and

FIG. 6 is a detail view of another embodiment of the invention.

Referring now to the drawings, the pressure vessel illustrativelycomprises a substantially cylindrical container 11 of rigid material,such as steel or aluminum, capable of withstanding the pressure to whichit is to be subjected in use.

The container has one end closed as at 12 and such closed end has anaxial port 13, the inner end 14 of which defines a valve seat.

The mouth 15 of the container is cylindrical as shown and the innersurface of the container adjacent the mouth 15 is threaded as at 16.

Positioned in container 11, is a deformable partition illustratively inthe form of an elongated bladder 23 of rubber or similar material havinglike characteristics which divides the container 11 into a gas chamberC, and a liquid chamber C-1. The bladder 23 is closed at one end as at24, and the mouth 25 of the bladder which is of greater thickness thanthe remaining portion of the bladder is secured as by molding to anannular supporting member 26 of rigid material, preferably of steel. Byreason of the molding of the bladder 23 to the annular supporting member26, the bladder 23 will be securely bonded to such supporting member 26.

It is to be noted that the transverse width of the annular supportingmember is greater than that of the thickened rim 25 of the bladder, sothat as clearly shown in FIG. 1, the outer periphery 32 of the annularsupporting member 26 will extend laterally outwardly of the outerperiphery 33 of the thickened rim 25.

As is clearly shown in FIG. 1 the inner diameter of the container isreduced to define an annular shoulder 34 which forms a seat for theouter periphery 32 of the annular supporting member 26 so that thebladder 23 will be dependably retained in desired position in thecontainer.

The annular supporting member 26 has an annular groove 35 in its outerperiphery in which an O-ring 36 is positioned, the function of theO-ring being to provide a seal.

In order to retain the annular supporting member 26 and bladder 23 inposition, a cylindrical cover member 38 is provided. As is clearly shownin the drawings, the cover member is substantially cup-shaped with itsside wall or skirt 39 of outer diameter just slightly less than thediameter of the wall portion 40 of the container so that the side wall39 may be readily positioned in the container.

The cover member 38 adjacent its outer surface is of slightly enlargeddiameter as at 41, and is externally threaded so that it may be screwedinto threaded mouth 15 of the container by means of a spanner wrench(not shown) applied to conventional bores 42' in the top surface 42 ofthe cover member 38.

As is clearly shown in the drawings, when the cover member is screwedinto the container, with the top surface 42 of the cover member flushwith the outer end 15 of the container, the inner end 43 of the sidewall 39 of the cover member will abut against the top surface 43' of theannular supporting member 26 to retain the latter on the annularshoulder 34.

The outer periphery of the side wall 39 of the cover member, has anannular groove 44 in which an O-ring 45 is positioned to define a sealbetween the side wall 39 and the inner surface of the container.

Mounted on the closed end 24 of the bladder 23 and axially positionedwith respect thereto is a valve member 47 illustratively in the form ofa button, preferably formed from steel or aluminum. The valve member isdesigned to abut against seat 14 to close the port 13 when the gaschamber C is charged with gas under pressure, as will be hereinafterdescribed.

According to the invention the cover member 38 has an axial bore 51therethrough of reduced diameter at its inner end, as at 52, defining anannular shoulder 53.

Positioned in the axial bore 51 is a gas valve assembly 50. The gasvalve assembly, as is clearly shown in FIG. 2 for example, comprises arigid cylindrical member preferably of steel having a cylindricalportion 54 at its inner end depending from integrally formed hubconfiguration 55, illustratively hexagonal in shape. The inner surface56 of hub 55 has an annular recess or groove 57 in which an O-ring 58 ispositioned.

Rising from the top surface 59 of hub portion 55 is a cylindricalportion 61 axially aligned with cylindrical portion 54 andillustratively of smaller diameter than the latter.

The cylindrical portion 54 is externally threaded as at 62 so that itmay be screwed into the correspondingly internally threaded portion ofthe reduced diameter portion 52 in the manner hereinafter to bedescribed.

As is clearly shown the valve assembly 50 has an axial bore 63therethrough which is of reduced diameter as at 64 adjacent its lowerend defining an annular shoulder 64' and then flares outwardly as at 65to define a beveled seat.

Positioned in the bore 63 is a valve stem 66 which has a body portion66a and a mounting portion 66b, the stem 66 being of a diametersubstantially less than that of bore 63.

Secured to the outer end 67 of stem 66 is a transversely extendingretaining bar 68 of length greater than the diameter of stem 66 so as todefine a retaining shoulder 69. An actuating pin 71 extends axiallyoutwardly from the center of cross bar 68.

The inner end of the body portion 66a of stem 66 has an axial recess 72therein which is internally threaded as shown. The mounting portion 66bcomprises a pin having one end screwed into threaded recess 72. Theouter cylindrical end 73 of mounting pin 66b is of enlarged diameterdefining an annular stop shoulder 74 having a sharp periphery 74'. Theend of enlarged diameter portion 73 has an enlarged diameter colar 75integral therewith, and a valve member or disc 76 in the form of anannular bead of resilient material such as rubber is bonded to the end73 of mounting pin 66b and the collar 75 which are completely embeddedin the resilient valve disc 76. It is to be noted that the outer plane76a of valve member 76 is aligned with the plane of shoulder 74.

As is clearly shown in FIG. 2, the valve member 76 has a roundedperiphery 77 and is of diameter such that the periphery would normallybe positioned slightly inwardly of the mouth or outer edge 78 of beveledseat 65 as shown in FIG. 2.

In order to retain the valve member 76 in its closed but relativelyunstressed position shown in FIG. 2, which is the first seating positionthereof, a coil spring 81 is provided encompassing the body portion 66aof stem 66 with one end of the coil spring abutting against theretaining shoulder 69 formed by cross bar 68 and the other end of thespring abutting against annular shoulder 64'.

As a result of the force exerted by such spring, the valve member 76will be urged inwardly to the position shown in full lines in FIG. 2which is the unstressed position of the valve member 76.

To complete the assembly, a cap 81 is provided which is internallythreaded so that it may be screwed on the externally threaded end 61 ofthe valve assembly.

The valve assembly 50 according to the invention may readily be mountedin the cover member 38 and also readily removable therefrom.

To mount the valve assembly it is merely necessary to utilize a socketwrench (not shown), the lower edge of which would engage the recesses 82in the top surface 59 of the hub portion 55. When the socket wrench isrotated the end 54 would be screwed into threaded bore portion 52 untilthe inner surface 56 of the hub 55 abuts against shoulder 53 at whichtime the )-ring 58 would be compressed to define a seal.

To charge the pressure accumulator above described, the cap 81a isremoved and a charging adaptor of conventional type (not shown) isscrewed onto the outer end portion 61. The charging adaptor carries aconventional axial pin which presses against the pin 71, forcing thevalve stem 66 inwardly into the container. As a result the valve member76 will be moved away from the beveled seat 65, to the position shown inbroken lines in FIG. 2.

As a result gas under pressure will be forced through bore 63, reducedbore portion 64 and beveled bore portion 65 into the gas chamber Cdefined by the bladder 23.

After the bladder 23 is charged, the charging adaptor is removed and thecap 81a screwed in place. As a result of the forces exerted by the coilspring 81 and the compressed gas in bladder 23 which will react againstthe inner surface 75a of valve member 76, the resilient valve member 76will first move to the position shown in full lines in FIG. 2 and thenwill continue to move inwardly due to the force exerted by the gas underpressure in the charged bladder, to the position shown in FIG. 4. Due tothe force exerted by the gas under pressure in the charged bladder 23,as is clearly shown in FIG. 4, the resilient valve member 76 will bedeformed so that its outer periphery will substantially conform to theconfiguration of the beveled bore portion 65.

In addition it is to be noted that the valve stem 66 will move outwardlyuntil the sharp periphery 74' of stop shoulder 74 abuts against thebeveled wall portion 65, thus providing a metal to metal seal.

Due to the fact that the pressure in the bladder 23 reacting against theresilient valve member 76 is greater than the pressure in bore 63, thevalve member 76 will define an O-ring seal at the junction between theedge 74' and the beveled wall 65, ensuring a highly dependable gas seal.

It is to be noted that since the surface 75a of the valve member issubstantially flush with the adjacent inner surface of cylindricalportion 54 and the rubber material forming the valve member 76 istightly pressed against the beveled seat 65 there will be no openingprovided which would permit extrusion of the bladder 23 if the lattershould fold across the inner end of the gas port when the liquid chamberC-1 is charged with oil under pressure.

In the embodiment shown in FIGS. 1-5, the valve assembly is part of aseparate casing screwed into the gas port. In the embodiment shown inFIG. 6, the valve assembly is located directly in the gas port.

In view of the similarity of the embodiment shown in FIG. 6 to theembodiment of FIGS. 1-5, corresponding parts have the same referencenumerals primed.

Referring to FIG. 6, the cover member 38' has an axial bore 63'therethrough of enlarged diameter at its outer end 50a defining anannular shoulder 50'a and of reduced diameter at its inner end as at 64'defining an annular shoulder 64".

Positioned in bore 63' is a gas valve assembly 50' which comprises avalve stem 66' having a body portion 66'a and a mounting portion 66'b,the stem 66' being of diameter substantially less than that of bore 63'.

Secured to the outer end 67' of stem 66' is a transversely extendingretaining bar 68' of length greater than the diameter of stem 66' so asto define a retaining shoulder 69'. An actuating pin 71' extends axiallyoutwardly from the center of cross bar 68'.

The inner end of the body portion 66'a of stem 66' has an axial recess72' therein which is internally threaded as shown. The mounting portion66'b comprises a pin having one end screwed into threaded recess 72'.The outer cylindrical end 73' of mounting pin 66'b is of enlargeddiameter defining an annular stop shoulder 74 having a sharp periphery74'. The end of enlarged diameter portion 73' has an enlarged diametercollar 75' integral therewith, and a valve member or disc 76' in theform of an annular bead of resilient material such as rubber is bondedto the end 73' of mounting pin 66'b and the collar 75' which arecompletely embedded in the resilient valve disc 76' .

As is clearly shown in FIG. 6, the valve member 76' has a roundedperiphery 77' and is of diameter such that the periphery would normallybe positioned slightly inwardly of the mouth or outer edge 78' ofbeveled seat 65' as shown in FIG. 6.

In order to retain the valve member 78' in its closed but relativelyunstressed position shown in FIG. 6, which is the first seating positionthereof, a coil spring 81' is provided encompassing the body portion66'a of stem 66' with one end of the coil spring abutting against theretaining shoulder 69' formed by cross bar 68' and the other end of thespring abutting against annular shoulder 64".

As a result of the force exerted by such spring, the valve member 76'will be urged inwardly to the position shown in full lines in FIG. 6which is the unstressed position of the valve member 76'.

To complete the assembly, a plug 81'a is provided which is internallythreaded so that it may be screwed into the internally threaded end 50aof the cover 38'.

Since the operation of the valve assembly of FIG. 6 is identical to thatof the embodiment of FIGS. 1-5, no further description is believednecessary.

Having thus described my invention, what I claim as new and desire tosecure by letters patent of the United States is:
 1. A pressure vesselcomprising a container of rigid material having two ports, both axiallyaligned with said container, one of said ports defining a gas port andthe other a liquid port, a partition intervening between said ports todefine a variable volume gas chamber and a variable volume liquidchamber in communication with said gas port and liquid port,respectively, means to close said liquid port, means to charge said gaschamber with gas under pressure, said charging means comprising a valveassembly mounted in the gas port, said valve assembly comprising a borehaving an inner end defining a valve seat, a valve stem slidably mountedin said bore, said stem being of dimensions such as to provide clearancefor gas flow through said bore, said stem having an inner end, a valvedisc of deformable resilient material mounted on said inner end of saidstem, resilient means reacting against said stem to urge the latteroutwardly to retain the outer surface of said valve disc against saidseat in a first seating position, and means rigid with said stem adaptedto abut against said valve seat when said valve disc is moved outwardlyto a second seating position as a result of gas pressure in said gaschamber, to limit the outward movement of said valve disc.
 2. Thecombination set forth in claim 1 in which the inner end of said bore isbeveled to define said valve seat, said bore being of larger diameter atits inner end, said valve disc is an annular bead having a peripherywhich engages said larger diameter inner end of said beveled valve seatin the first seating position of said valve disc.
 3. The combination setforth in claim 1 in which the inner end of said bore is beveled todefine said valve seat, said valve seat being of larger diameter at itsinner end and of smaller diameter at its outer end, the inner end ofsaid valve stem extends into the valve seat and has a cylindricalportion of diameter greater than said smaller diameter outer end portionof said beveled seat, said stem having a cylindrical portion adjacentits inner end, said valve disc is an annular bead secured to saidcylindrical portion of said stem, said bead having a periphery engagingsaid larger diameter portion of said beveled seat in the first seatingposition of said valve disc, said cylindrical portion of said stemengaging the smaller diameter outer end portion of said beveled seat ina second position of said valve disc, said bead being deformed into thebeveled portion of said bore in the second seating position of saidvalve disc.
 4. The combination set forth in claim 1 in which said borehas a reduced diameter portion near its inner end defining a shoulder,said stem has an outer end having an abutment, a coil springencompassing said stem and reacting against said abutment and saidshoulder, normally urging said stem outwardly to move said valve disc toits first seating position.
 5. The combination set forth in claim 1 inwhich said gas port comprises an additional bore having an inner end ofreduced diameter defining an annular shoulder, said reduced diameter endof said bore being internally threaded, said valve assembly comprises acasing of rigid material having said first named bore extending axiallytherethrough, said valve assembly having a transversely extending hubwith externally threaded cylindrical portions extending axially fromboth sides thereof, one of said cylindrical portions being screwed intothe reduced diameter bore portion, said first named bore extendingthrough said cylindrical portions of said hub.
 6. The combination setforth in claim 5 in which said hub defines opposed surfaces, the surfaceof said hub adjacent the cylindrical portion screwed into the reduceddiameter bore portion has an annular recess in which an O-ring ispositioned, said O-ring being compressed against said annular shoulderwhen the cylindrical portion is tightened to define a seal.